Film and cameras that are all in one, commonly referred to as single-use or one-time-use cameras, have recently become well known. Typically, the one-time-use camera is a simple point-and-shoot type comprising a plastic, inner, main body part which supports a fixed-focus taking lens, a film metering mechanism with a rotatably supported metering sprocket, a manual film advance thumbwheel, a single-blade shutter, a manual shutter release button, a frame counter for indicating the number of exposures remaining for picture-taking, a direct see-through viewfinder, and possibly an electronic flash unit. Plastic front and rear cover parts often house the main body part between them to complete the camera assembly, and the rear cover part connects to the main body part and/or to the front cover part to make the main body part light-tight. A decorative cardboard outer box contains the camera assembly and has respective openings for the taking lens, the shutter release button, the film advance thumbwheel, the viewfinder, the frame counter, and a flash emission window.
Typically, during original manufacture or recycling (remanufacture) of the one-time-use camera, a conventional light-trapping film cassette with a 35 mm filmstrip having a film leader protruding from the cassette shell, and a film take-up spool to which a leading end of the protruding film leader is attached, are placed in respective chambers in the main body part. The protruding film leader is positioned over the metering sprocket to place one of a longitudinal series of edge perforations in the leader onto one of an annular series of peripheral teeth on the metering sprocket in order to engage the leader to the metering sprocket. Then, the rear cover part is fitted to the main body part to prevent the protruding film leader from becoming separated from the metering sprocket, and as disclosed in prior art U.S. Pat. No. 4,972,649, issued Nov. 27, 1990, an exposed end of the film take-up spool is rotated to factory prewind substantially the entire length of the unexposed filmstrip from the cassette shell onto the take-up spool. Lastly, the outer box is placed on the camera assembly.
After the photographer takes a picture with the one-time-use camera, he or she manually rotates the thumbwheel to rotate a cassette spool inside the cassette shell to rewind the exposed frame into the cassette shell. The rewinding movement of the filmstrip the equivalent of slightly more than one frame width rotates the metering sprocket, which is in engagement with the filmstrip, to decrement the frame counter to its next lower-numbered setting. When the maximum number of exposures available on the filmstrip are exposed and the filmstrip is completely rewound into the cassette shell, the one-time-use camera is given to a photofinisher who tears the outer box off the camera unit, separates the rear cover part from the main body part, and removes the film cassette with the filmstrip from the main body part. Then, he removes the filmstrip from the cassette shell to develop the negatives and make prints for the customer, and he forwards the used camera parts to the manufacturer for recycling.
As contrasted with the conventional light-trapping film cassette, prior art U.S. Pat. No. 5,357,303, issued Oct. 18, 1994, discloses a new-type film cassette having a light lock which is pivoted closed to prevent ambient light from entering the cassette interior and is pivoted open to permit film movement out of and into the cassette interior. An implement or tool is designed to engage the light lock to pivot it open and closed.
Prior art U.S. Pat. No. 5,231,438, issued Jul. 27, 1993, discloses a camera intended for use with the new-type film cassette having a light lock which is pivoted closed to prevent ambient light from entering the cassette interior and is pivoted open to permit film movement out of and into the cassette interior. The camera has a release button which when manually moved in a releasing direction actuates a latching device. The latching device normally secures a door closed over a chamber holding the film cassette. However, when the latching device is actuated, it operates to pivot the light lock closed and to release the door to uncover the chamber.